solve 

sudoku 
step
1 2
3 4
5 6
7 8
9 10
<home 
explanations: 
this
is step 8


The 6's in r4 and r6 with the 6 in c2 fix the 6 box 4 at c1r5. Box 4 now has only two cells free for a 1 or a 2. Because r6 already has a 1 in it, cell c2r6 must be a 2 leaving c2r5 for the 1. (entered in step 9) .Now we know the 1 in box 4 has to be in c2, the 1's in c3 and r7 position the 1 in box 7 in cell c1r9 This leaves two cells free in box 7 for a 2 and 7. c3 already has a 7 so c3r9 must be a 2 and therefore c1r7 a 7 and then only one space left in row 7 for a 2 (entered in step 9)



